Sequestering composition containing a corrosion inhibitor



United States SEQUESTERING COMPOSITION CONTAINING A CORROSION INHIBITOR Homer W. McCune, Wyoming, Ohio, assignor to The Procter & Gamble Company, Cincinnati, Ohio, a corporation of Ohio No Drawing. Application July 2, 1956 Serial No. 595,118

6 Claims. (Cl. 252-110) This invention relates to the protection of aluminum, zinc, and German silver from the action of certain organic chelating agents.

These organic chelating agents are alkaline salts of amino polycarboxylates such as ethylene diamine tetra acetic acid, N-hydroxy ethyl ethylene diamine triacetic acid and nitrilo triacetic acid. These chelating agents may be used in place of calcium sequestering phosphates in detergent compositions employing either the alkali sapom'fied fatty-type soap or the synthetic detergents.

They are also used in textile processing to chelate or sequester metals, for cleaning boilers of calcium scale, and for many other uses where the chelating of metals and alkalineearth metals is desired. Chelation is a specific type of sequestering in which a ring compound is formed by the sequestered ion closing the ring.

While these chelating agents will sequester metals, generally, they are more effective than most complexing agents in reacting with alkaline earth metals. The term metal sequestering as used herein and in the claims will refer to this reaction of alkaline earth metal ions with atent The amino carboxylates may be represented by the following formula:

NCHQY MO 0 c on,

where M is an alkali metal ion, ammonium or substituted I ene, triethylene or tetraethylene glycol. The'alkyl'polyethylene glycol phosphates can be used at a level of from about 3% to about 40% of the calcium sequestering amino polycarboxylates sequestrants and provide some retarding of corrosion at all levels within this range. The preparation of the reaction products of ethylene oxide and fatty alcohols is well known. It is described in US. Letters Patent 1,970,578, granted to Conrad Schoeller and Max Wittiwer on August 21, 1934, and US. Letters Patent 2,133,480, granted to Conrad Schoeller and Joseph Nusslein on October 18, 1938. The phosphation of the ethers thus prepared is carried out by adding phosphorus oxychloride slowly to the ethers in a well stirred closed vessel. Nitrogen is commonly used to blanket the reactants from contact with air and to sweep the hydrochloric acid formed in the reaction from the vessel.

The phosphated alkyl polyethylene glycols may also be represented by the formula R(OC H OPO MN where R is an alkyl group of 14 to 22 carbons, x is an integer from 1 to 7, M and N are taken from the group H, Na, K, NH and alkylol substituted ammonium in which the alkylol is ethanol, propanol and isopropanol and the degree of substitution is mono, di, and tri.

The phosphated alkyl ethylene oxide condensation products described in the example below were made by condensing the indicated amount of ethylene oxide with fatty alcohol made from sperm oil,*which in the process of reducing the fatty acids in the sperm oil to alcohol was hydrogenated to an iodine value less than 1. The alcohols were thus primarily those of 14, 16, 18 and 20 carbons, with about 1% of C alcohols. The term hardened sperm-alcohol is used to describe this product which contains the alcohols normally occurring in sperm oil, hydrogenated to an iodine value of less than 1, as well as the saturated fatty alcohols produced from the fatty acids of sperm oil.

EXAMPLE I r The inhibited composition (composition A) contained,

all parts by weight:

product of 2 moles of ethylene oxide with 1 mole of hardened sperm alcohol 20 parts of sodium sulfate 5 parts of water A blank was made in which the same amounts of the same ingredients were used, except that the 5% of phosphated alkyl ether, sodium salt, was replaced by sodium sulfate. The blank is called composition B.

Corrosion tests were made with product concentrations of 0.5% in 7 grains of hardness (CaCO equivalent) per gallon water, 3 hours at 140 F. for the aluminum and zinc; and 1.7 hours at 110 F. for the German siliver. The aluminum was The Aluminum Corp. of America 303'alloy (formerly 38) which contains 1.2% of manganese. The zinc was special high grade. The German silver was 10% nickel, 18% zinc, and 72% copper. All

pieces were 7.6 cm. long, 1.9 cm. wide and 0.1 cm. thick.

The test pieces were polished-with steel wool, followed by wet pumice, and then washed with water and alcohol. After fair drying they were weighed on an analytical balance. They were immersed in 200 milliliters of s'o'lu tion'in a'250 ml. Erlenmeyer flask. The strips were leanf ing at an angle to the bottom of the flask of about 40. The flasks were held at 140 F. for three hours, unless otherwise noted. After the tests all strips were removed and washed in water. The aluminum strips were then im- The corrosion tests were carried outas described in Example I.

Results of corrosion tests mersed in concentrated nitric acid'for three minutes to Aluminum Zinc German Silver remove products of corrosion. The aluminum strips were then washed in water and alcohol, air dried and weighed Wt, Wt. Wt. again. After the initial water wash the other metals were 3F 21 Appearance {$52 Appearance {Q252 Appearance washed'in alcohol, air dried and weighed again. The zelght loss in rrnlllgrams, listed below as .lossmgs. (Mm L3 g ly 0.8 Uh OA Unas thus determmed. Drscolored. changed. changed. 7 (B)..- 49' Badly Dis- 11 Etched 1.8 Dlscolored; Results of COTI'OSIO" tests colored. 7

Aluminum Zinc Silver 15 The com-position B appears quite corrosive but when Wt inhibited with the phosphated alkyl polyglycol, as in A, Int/ins Appearance Ifizss Appearance li/fss Appearance the con-0510p 1s gmatly reduced- .EXAMPLE IV (A)-.. 1.4 Slifihtly as 1 d 0.1 17 d 20 The basic formula was:

15- 0 auge 0 ange colored. 52.4 parts of an amino polycarboxylate sodium salt-4 B 45 13 (ll D 6.9 Et h d 1.4 $1 htl r was he 8 15%.. Y we used 7 colored. Sequestrant used:

, Esodium salt of ethylene diamine tetra acetate The effectiveness of the inhibitor in reventin corrosion V-sodium salt of N-hydroxyethyl ethylene dio a g n u I is particularly Stllkll'lg on the aluminum test pieces, 1.4 amlne trlacetic acid milligrams vs. 45 milligrams. P-sodium salt of a hydroxy low molecular alkyl H stamens;sasriszittz The inhibited composition A contained the following, 17.8 parts of sodium salt of polypropylene benzene sulall parts by weight: fonate where the polypropylene averages C 7 30 parts of the sodium salt ofthe sulfated reaction product Parts of .sodmm salt q P h reaction product of 3 moles of ethylene oxide and 1 mole of middle -of.2,moles of ethylene oxide with 1 mole of hardened cut coconut alcohol containing at least 65% C Sperm 9 30 parts of sodium salt of nitrilo triacetate The four preparations-E, V, P, and N-were made 30 parts of sodium sulfate to the above formula, and for each a blank was prepared 10dpats gf4the slodmr? salt10f phosplhateigeactionlpro; indwhich 1tfhe'fphospha'tecl alkyl ether was. replaced by no 0 mo es o e y ene 0x1 e W1 A mo e D so rum su ate. hardened sperm alcohol 40 Each preparation was dissolved in water to a concen- A m r made 252222.23 922:? 35.5? 522 2; as: assistant same .amounts 0 t e same lngre lents were use except l r that thephosphated ether was replaced by Sodium Sulfate. previously described uslng alumlnum. The results were. The corrosion tests were made as described in Example I. Weight Loss Appearance Result of corrosion tests Milligrams w 0.2Uh d. Mummum 2111 German Silver E Blank 27. 0 Diisioicirifii and etched.

' "first; ai'ii i$iii3l2 IY s s Appearance Eg s Appearance mis s, Appearance P "I" 0:7 Slighnymsmlmd' i a g y scoore (A)... 5.7 Discolored 3.8 Sgglhtly 0.4 Sgghtly tori red, mix d, The blank in ,each case indicates the corrosiveness of 20 Dlswlofed Etched-m 'Dismloredthe corresponding organic sequestrant when uninhibited.

The inhibiting effect of the phosphated alkyl poly- XA P .111 ethylene glycol is not limited to detergent compositions containing anionic detergents as is shown by the follow- Inlnbrted Composition A: ing example. 10 parts of sodium salt of polypropylene benzene sul- EXAMPLE v 1 fonate A composition similar to E'above was made using in 8 parts of sodium saltof tallow alcohol sulfate place of the alkyl benzene sulfonate a nonionic. This 52 parts of the 2 H O hydrate of "sodium ethylene diwas Sterox CD, a tall oil-ethylene oxide condensation amine tetra acetate product made by Monsanto Chemical Company. The 20'parts of sodium sulfate 7 formula was: I 6 parts of the sodium salt of the'phosphated'reaction 52.4 pans of sodium Salt of ethylene diamine tetra product of 4 moles of ethylene oxide with 1 'mole of acetate hardened spelrm alcohol 17.8 parts of Sterox CD 1 3 Parts of monoethanolanude coconurt fatty aclds 5.9 parts of the sodium salt of the phosphated reaction l-part of carboxymethyl cellulose p product of 2 moles of ethylene oxide to 1 mole of Composition B was made from the same amount-of the hrarpdenedisperm same ingredients as composition A except that sodium This was dissolvedin water to give 'a concentration sulfate replaced the sodium salt of the phosphated alkyl of 0.06%. ofSterox CD. ,A corrosion test on'aluminum ether. p as described in-Example lwasmade. 'Theloss'in' weight the examplesya widerange of synthetic detergents may be used. The following is by way of example.

' EXAMPLE VI 4 Class Typified by- 'Tests were made with strips of the aluminum described 5 in Example I. The area Of the strips was 29 square Alkyl nryl sulionates Sodium polypropylene benzene centimeters. The strips were immersed in 200 millig g tgegg gg gj Pmypmpyl' liters of solution at 60 C. for three hours. The solu- Alk'ylsulfatem; Sodiurnlainylsultate. tions were made with distilled water and were adjusted to f 55 51 ggggg fggggfl ig gg a pH of 9.5 atthe start of the test. 10 fate). v lsethionates Coconutesteroisodiumisethlonate. Monoglyceride sulfonat Dodlcfcyl either of propanol-Z-sodium Sll 0118 e. Wt. Sullnacetates Coconut ester of sodium sulioace- Composition Lossi Appearance 7 t gs. Alkyl glyceryl ether sulfonates Dodefeyl ether of propanol-2 sodium SH 0113. 8. V Sulionated Fatty Amides Laurie monoethanol amide sodium 0.18% sodium ethylene diamine tetra acetate. 45 Badlly dssulfate,

. co ore 0.18% sodium ethylene-diamlnetetraacetate 0.6 Slightly disgi gg fgi gfgyg; -}g,g ;g;;3g Examples of nonionic synthetic detergents are the folto 1 mole of hardened sperm alcohol. lowmg,

This shows the effectiveness of the'phosphated reaction Class Typified Byproducts of ethylene oxide and the higher molecular V b alcohols in preventing corrosion of aluminum by the Payethymne glycfls qgt g fgg molewlm' ethylene diamine tetra acetate salts in the absence of any Polyethyo'xy esters of fatty acids Stearic aeid condensed with5moles d t r em w of ethylene oxide.

5 e g Ethanol amides Mfortitoethanlol amide of coconut a y ac! s. EXAMPLE VII Polyethoxyethers of fatty alcohols- Dodecyl alcohol condensed with 5 x e h DIXQlIOIOS oie thyllene gycol.d h Under the same test conditions as used in Example ,,.,h32;ff" My condensation finife oiefiyhei mfr'i wit 3 VI, compositions containing soap were tested in distilled wat r solutions.

e .The: alkyl polyethylene glycol phosphates are anionic compounds and cannot be used in detergent compounds Wt. comprising cationic detergents, as the cationic comcomplsltmn lig Appearance pounds and anionic compounds combine stoichiometrically to form an inert compound. Further, when amino poly- (A) carboxylates are used with cationic detergents, the alkyl 0187 6 th 1 fr t t H polyethylene glycol phosphates are not eifective as cor- .SCI llllll e y 0118 rarmne e 1'8 866 a Ban mwgsodmm wuowsoup 26 ll r yro l n inhi itors- 40 Tests have been made with a phosphated octadecyl (B) ethylene oxide condensate and it is as effective in corgegg; sogium ethylene diamine tctra acetate" rosion resistance and tarnish inhibition as the hardened 3 F 2 g a,fi ggg i a g a an Dummy sperm alcohol preparations. The typical composition of product of 2 moles of ethylene oxide to l hardened sperm O11 alcohol 1S2 mole of hardened sperm alcohol. 4

5 Pct. C alcohols 4.5 0.18% sodium ethylene diamine tetra acetate 2 Discolored C l h l 29 0 2 a l 16 %sodiumcotonu soap 18 alcohols 52 C alcohols 13.5 0.18% sodium ethylene diamine tetra acetate C23 316011018 1 0.12% sodium coconut soap 0.02% sodium salt of the phosphate-d reaction 0.1 Slightly disprodnet of 2 moles oi ethylene oxide to 1 colored. 100 mole ol hardened sperm alcohol.

We have used preparations made with coconut alcohol 55 and find them much less effective' evidentl the lar e i example Shows the efiecnyeness offhe phosphated amount of C and lower alcohols reduce tli e efiectivireacnon Qmducts ethylene oxide and hlgher moiecqlar ness. The range of alkyl radicals useful is from 14 to 22 alcohols in reducing the corrosion of ethylene diamine carbons other alcohols such as those from the tetra acetate in the presence of soap. reaction may be utilized Detergent P L which the acnve mgrefhetft The alkaline material used to neutralize the carboxyl- IS a soap, an anionic synthetic detergent or a noniomc ic acids may be any one that yields a Soluble pub/Cap synthet c, or a mixture of soap and synthetic detergent, boxylate, sodium, potassium and ammonium being the and Whlch POlYCaPbQXYIateS f F? most useful. The alkylol substituted ammonias may be acetate P be Improved m corroslon mhlbmon used where a high degree of solubility is desired, as in a by the addltlOXl of phosphated alkyl polyethylene glycol liquid detergent. The alkylols may be ethanol, propanol ethers and may be subst1tu ted for the detergent composior isopropanol and the degree f substitution may b trons of any of the foregoing examples with comparable mono. or in results. Alternatively, comparable results are obtained It is f ibl to add the phosphated alkyl polyglycol y omission of the detergent Components from the Speclfic ethers to an alkaline detergent solution without previously examples. neutralizing the two hydrogens of the phosphate that are y detergent meant the sodium and potassmm soaps not esterified to the polyglycol radical. Thus the phosof fatty acids from oils of the coconut group, from tallow, phated polyglycol ethers are neutralized with the alkali from grease and from palm oil, (soluble soaps) and the of the polycarboxylate. Alternatively, the phosphated synthetic detergents both anionic and nonionic. alkyl polyglycol ethers may be neutralized before adding In addition to the synthetic detergents mentioned m to the amino polycarboxylates with sodium potassium,

. '7 ammonium oralkylol substituted ammonium; "The alkyle ols may be ethanol, propanolor isopropanol'andthe degree of substitution may be mono-, di-, ortri.

It may be desirable to neutralize only one of I gens, for pH adjustment for instance.

Having thus described'my lnvent o mwhat I claim isz l. A sequestering composition of inhibited corrosiveness, as usedin dilute aqueous alkaline medium, toward aluminum, zinc and German silver, consisting essentially of a calcium sequestering amino polycarboxylate which is a soluble salt of an amino polycarboxylieacid selected from the group consisting of ethylene diamine tetra 'car-' boxylic acid, hydroxy alkylethylene diamine 'tric'a'rboxylic acid, and nitr-ilo tricarboxylio-acid in which the carboxylic acids contain 2 carbon atoms, and as an inhibitor of corrosion a compound of the formula where R is an alkyl group of 14 to 22 carbons in chain length, x is 1 to 7, M and N are taken from the group H, Na, K, NH and alkylol substituted ammonium in which the number of alkylol substituents is 1 to 3 and the nu1nber of carbon atoms in each alkylol' substituent is 2' to 3, said inhibitor being present in amounts of from about 3% to about 40% of said aminopolycarboxylate.

2. The composition of claim 1 in which the calcium sequestering amino polycarboxylate is ethylene diamine tetra acetate. r

3. The composition of claim 1 in which the calcium sequestering amino polycarboxylate is N-hydroXyethyl ethylene diamine triacetate.

4. The composition of claim 1 in which the calcium the hydroq s ri amino p yca b yla is n rqlo t acc ate 5. The composition of claim 1 in which R is a mix: ture of C and C straight chain alkyls.

6. The composition of claim 1' in combination with a .detergent selectedfr om .the group consisting of soluble soaps; anionic nonrsoap .synthetic detergents, fno'nionic synthetic-"detergentg'land mixtures thereof.

i Rs q nwsc td the file r th P t UNITED' STATES PATENTS 2,167,867 Benning 2..-; Aug-1, 1939 r 2,224,695 Prutton Dec. 10, 1940 2,240,957 Munz "May 6, 1941 2,257,186 Orthner et ,al. Sept. 30, 1941 2,285,853 Downing June 9, 1942 2,315,072 Nelson et al. Mar.'30, 1943 2,346,154 Denison et a l. Apr. 11, 1944 2,403,765 Smith et al. July 9, 1946 2,651,829 Nusslein Sept. 15, 1953 2,665,995 Bishop Jan. 12, 1954 ,7 ,6 5 V Vau i-'--.--'. -.'.-A- :-l-t- I FO E G P E TS 421,568 Canada Iuly'18, 1944 OTHER REFERENCES Handbook of Chemistry and Physics, 28th ed. pp. 1215, 1216, pub. by Chemical Rubber Pub. Co., Akron, Ohio (1944). j y Sequestrene, pp. 1 and 39, pub. by Geigy Chem. Corp., NY. (1952). 

1. A SEQUESTERING COMPOSITION OF INHIBITED CORROSIVENESS, AS USED IN DILUTE AQUEOUS ALKALINE MEDIUM, TOWARD ALUMIUUM, ZINC AND GERMAN SILVER, CONSISTING ESSENTIALLY OF A CALCIUM SEQUESTERING AMINO POLYCARBOXYLATE WHICH IS A SOLUBLE SALT OF AN AMINO POLYCARBOXYLIC ACID SELECTED FROM THE GROUP CONSISTING OF ETHYLENE DIAMINE TETRA CARBOXYLIC ACID, HYDROXY ALKYL ETHYLENE DIAMINE TRICARBOXYLIC ACID, AND NITRILO TRICARBOXYLIC ACID IN WHICH THE CARBOXYLIC ACIDS CONTAIN 2 VARBON ATOMS, AND AS AN INHIBITOR OF CORROISON A COMPOUND OF THE FORMULA
 6. THE COMPOSITION OF CLAIM 1 IN COMBINATION WITH A DETERGENT SELECTED FROM THE GROUP CONSISTING OF SOLUBLE SOAPS, ANIONIC NON-SOAP SYNTHETIC DETERGENTS, NONIONIC SYNTHETIC DETERGENTS, AND MIXTURES THEREOF. 